Response of understory vegetation and tree regeneration to a single prescribed fire in oak-pine forests

Successful fire exclusion since the 1940s has contributed to shifts in understory species composition in oak-pine forest communities in the Cumberland Plateau of Kentucky, USA, exemplified by a lack of oak (Quercus L.) regeneration and an increase in regeneration of fire-sensitive species. On ridgetop sites in Daniel Boone National Forest, the U.S. Forest Service is using prescribed fire to maintain oak-pine communities, a management practice that could also affect understory species composition and richness. We examined the four-year effects of a single, late-winter prescribed fire on understory vegetation and tree regeneration. There was a nonsignificant trend of increased species richness in burned areas, mostly due to an elevated number of herbaceous species. There were no significant effects of fire on herb and shrub cover. Higher densities of oak, yellow-poplar (Liriodendron tulipifera L.), and red maple (Acer rubrum L.) seedlings in burned areas occurred only in the second growing season after fire. Total sprouting, especially of red maple and flowering dogwood (Cornus florida L.), was higher for two growing seasons following fire. Fire promoted regeneration by fire-tolerant and fire-intolerant species alike. The use of prescribed fire to maintain density of fire-tolerant tree species and reduce proliferation of fire-intolerant tree species will probably require more frequent fires, higher intensity fires, or both.